JP2011018717A - Apparatus and method for resist application - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus and a method for resist application wherein spots of resist are deposited in a concentric pattern on a disk substrate, and the resist is applied simultaneously to both sides of the disc.SOLUTION: The apparatus for resist application includes a disk substrate rotating motor having a rotating shaft which is inserted removably into the through-hole of the disk substrate having the through-hole in the center, two inkjet heads provided on the obverse and reverse sides, respectively, of the disk substrate such that the heads are not in contact with the sides, and a carriage for causing the two inkjet heads to move radially inward and outward with respect to the disk substrate. The disk substrate having a through-hole in the center is applied over the rotating shaft of the disk substrate rotating motor, the inkjet heads are arranged on the obverse and reverse sides of the disk substrate such that the heads are not in contact with the sides, and then the inkjet heads are moved radially inward and outward with respect to the disk substrate while the disk is rotated by the disk substrate rotating means.

Description

  The present invention relates to an apparatus for applying a resist to the surface of a transfer object and a method for applying the resist in a nanoimprint apparatus that forms a fine structure on the surface of the transfer object. More specifically, the present invention relates to a nanoimprint apparatus for forming a fine structure on the surface of a transfer object such as a donut-shaped disk-shaped disk substrate, and a device for simultaneously applying a resist on both sides of the disk-shaped disk substrate and the resist. Regarding the method.

  With the remarkable improvement in functions of various information devices such as computers, the amount of information handled by users is steadily increasing and has reached the tera unit range from giga. Under such circumstances, there is an increasing demand for semiconductor devices such as information storage / reproduction devices and memories having higher recording density than before.

  In order to increase the recording density, a finer processing technique is required. The conventional photolithographic method using an exposure process can finely process a large area at a time, but since it does not have resolution below the wavelength of light, it naturally has a microstructure below the wavelength of light (for example, 100 nm or less). It is not suitable for making. As a processing technique for a fine structure having a wavelength equal to or less than the wavelength of light, there are an exposure technique using an electron beam, an exposure technique using an X-ray, an exposure technique using an ion beam, and the like. However, the pattern formation by the electron beam drawing apparatus is different from the batch exposure method using a light source such as i-line or excimer laser, and the more patterns to be drawn by the electron beam, the longer the drawing (exposure) time is. . Therefore, as the recording density increases, the time required to form a fine pattern becomes longer, and the manufacturing throughput is significantly reduced. On the other hand, in order to increase the speed of pattern formation by an electron beam lithography system, the development of a collective figure irradiation method that irradiates an electron beam in a batch by combining masks of various shapes is progressing. The size of the electron beam drawing apparatus using the method is increased, and a mechanism for controlling the position of the mask with higher accuracy is further required, which increases the cost of the drawing apparatus itself and consequently increases the medium manufacturing cost. There are problems such as.

  As a processing technique for a fine structure having a wavelength equal to or less than the wavelength of light, a method using a printing technique has been proposed instead of the conventional exposure technique. For example, Patent Document 1 describes an invention related to “nanoimprint lithography (NIL) technology”. Nanoimprint lithography (NIL) technology uses a processing technique for fine structures below the wavelength of light, such as an electron beam exposure technique, to press a master (mold) with a predetermined fine structure pattern onto a resist-coated transfer substrate in advance. In this technique, the fine structure pattern of the original plate is transferred to the resist layer of the substrate to be transferred. As long as the original plate is available, there is no need for a particularly expensive exposure device, and replicas can be mass-produced with a normal printer-level device, so throughput is dramatically improved compared to electron beam exposure technology, etc., and manufacturing costs are greatly increased. Reduced to

  In the case of using a thermoplastic resin as a resist in the nanoimprint lithography (NIL) technique, the material is transferred by pressurizing it at a temperature near or above the glass transition temperature (Tg) of the material. This method is called a thermal transfer method. The thermal transfer method has an advantage that a general-purpose resin can be widely used as long as it is a thermoplastic resin. On the other hand, when using a photosensitive resin as a resist, it transfers with the photocurable resin which hardens | cures when exposed to light such as ultraviolet rays. This method is called an optical transfer method.

  The photoimprint type nanoimprint processing method requires the use of a special photo-curing resin, but the advantage of reducing the dimensional error of the finished product due to the thermal expansion of the transfer printing plate and printed material compared to the thermal transfer method. There is. In addition, the equipment does not require a heating mechanism or additional devices such as temperature rise, temperature control, and cooling, and the nanoimprint equipment as a whole is also designed with consideration for thermal distortion countermeasures such as heat insulation. There are advantages such as no longer needed.

  An example of an optical transfer type nanoimprint apparatus is described in Patent Document 2. This apparatus is configured such that a stamper capable of transmitting ultraviolet rays is pressed against a substrate to which a photocurable resin is applied, and ultraviolet rays are irradiated from above. A predetermined fine structure pattern is formed on the transfer substrate pressing surface of the stamper.

  FIG. 7 is a schematic diagram showing the steps of a fine structure transfer method using a light transfer type nanoimprint technique. In step (a), a transfer object 100 having a resist 104 coated on the upper surface of the substrate 102 is prepared, and a stamper 108 having a fine pattern 106 formed on the side in contact with the resist 104 is connected to the transfer object 100. Make them confront. In step (b), the stamper 108 is pressed against the resist coating surface of the transfer object 100. In step (c), ultraviolet (UV) light is irradiated from the upper surface of the stamper 108 to cure the resist 104. Next, in step (d), the stamper 108 is peeled from the transfer target 100. Thus, the pattern layer 110 is formed on the surface of the substrate 102 of the transfer target 100. The pattern layer 110 is an inverted image of the fine pattern 106 of the stamper 108.

  The stamper 108 is made of a light transmissive material. It can be made of a hard material such as glass, quartz or sapphire, or a flexible and elastic material such as a polymer. The substrate 102 is made of a known and common material such as silicon, glass, aluminum alloy, or synthetic resin. The substrate 102 is, for example, a donut-shaped disk-shaped disk substrate having a through hole formed in the center, such as an HDD, CD, or DVD. If necessary, a conventional thin film such as a metal layer, a resin layer, or an oxide film layer may be formed on the surface of the substrate 102 to form a multilayer structure. As the resist 104, for example, a synthetic resin material added with a photosensitive substance can be used. As the synthetic resin material, for example, cycloolefin polymer, polymethyl methacrylate (PMMA), polystyrene polycarbonate, polyethylene terephthalate (PET), polylactic acid (PLA), polypropylene, polyethylene, polyvinyl alcohol (PVA), etc. can be used. Examples of the photosensitive substance include peroxides, azo compounds (for example, azobisisobutyronitrile), ketones (for example, benzoin, acetone, etc.), diazoaminobenzene, metal complex salts, dyes, and the like. It is done. As a method for applying the resist 104 to the substrate 102, for example, a dispensing method, a spin coating method, an ink jet method, or the like can be used. The dispensing method is a method in which the substrate 102 is directly immersed in a resist solution, but has a drawback that the resist film thickness becomes non-uniform. The spin coating method is a method in which a substrate is adsorbed from the back surface and rotated, a resist solution is dropped at the center, and the whole surface is spread by centrifugal force. In the case of this method, there is a drawback that the resist solution wraps around from the collecting end surface to the back surface, and it is difficult to apply both surfaces uniformly. Moreover, although the dispensing method and the spin coating method can apply a resist to the entire surface of the substrate, it is not possible to apply a resist like a dot pattern to a specific portion. The ink jet method uses an ink jet printer, and a resist is applied to the substrate surface from the ink jet head while scanning the ink jet head or the substrate in the XY plane. The inkjet method is an economical method that can apply resist in a dot pattern, accurately control the amount of resist applied, and avoid applying resist solution waste as much as possible because it is applied only where needed. is there.

  However, when applying a resist to a donut-shaped disk-shaped disk substrate with a conventional ink jet printer, the application work can be performed only on one side, and the work efficiency is low. Further, since the resist 104 is applied while scanning the inkjet head or the substrate in the XY plane, the resist 104 is arranged linearly with respect to the XY plane, and this pattern and the fine pattern 106 of the stamper 108 are concentric. There is a disadvantage that a spot of the resist 104 that does not match is generated. Since the presence of a resist spot that does not match the fine pattern 106 of the stamper 108 results in a decrease in performance of a magnetic disk or the like as a final product, the resist 104 is applied so as to completely match the fine pattern 106 of the stamper 108. Is strongly demanded.

US Pat. No. 5,772,905 (US005772905A) JP 2008-12844 A (P2008-12844A)

  Accordingly, an object of the present invention is to provide a resist coating apparatus capable of arranging resist spots concentrically with respect to the center of a donut-shaped disk-shaped disk substrate and simultaneously applying a resist on both surfaces of the substrate. is there.

  Another object of the present invention is to provide a resist coating method in which resist spots can be arranged concentrically with respect to the center of a donut-shaped disk-shaped disk substrate, and a resist can be simultaneously coated on both sides of the substrate. is there.

  The problem is that a disk-shaped disk substrate rotation motor having a rotation shaft inserted into and removed from the through-hole of a disk-shaped disk substrate having a through-hole at the center, and non-contact on both sides of the front and back surfaces of the disk-shaped disk substrate This is solved by a resist coating apparatus having two inkjet heads arranged in a state and a carriage for moving the individual inkjet heads back and forth in the radial direction of the disk-shaped disk substrate.

  Another problem is that a disk-shaped disk substrate having a through hole at the center is inserted into the rotation axis of the disk-shaped disk substrate rotating motor, and two inkjet heads are installed on both the front and back surfaces of the disk-shaped disk substrate. Solved by a resist coating method which is arranged in a non-contact state and moves the two inkjet heads back and forth in the radial direction of the disk-shaped disk substrate while rotating the disk-shaped disk substrate by the disk-shaped disk substrate rotating motor. Is done.

  According to the resist coating apparatus and the resist coating method of the present invention, two inkjet heads arranged on both the front and back sides of a disk substrate are rotated while rotating a disk-shaped disk substrate having a through hole in the center. The resist can be applied concentrically with respect to the disk-like disk substrate by advancing and retreating in the radial direction, and the resist can be simultaneously applied to both the front and back surfaces of the disk substrate. As a result, the resist coating pattern can be completely matched with the fine pattern of the stamper, and the time required for the coating operation can be halved.

It is a top view of an example of the resist coating apparatus of the present invention. FIG. 2 is a front view of the resist coating apparatus shown in FIG. 1. It is a block diagram which shows an example of control of the resist coating method by this invention. (A) is a partially enlarged schematic plan view of a resist pattern applied by the prior art, and (b) is a partially enlarged schematic plan view of a resist pattern applied by the resist coating apparatus of the present invention. It is a front view of another example of the resist coating apparatus of the present invention. It is a partial expansion outline top view of another example of the resist pattern apply | coated with the resist coating apparatus of this invention. It is a schematic diagram which shows the process of the fine structure transfer method by the nanoimprint technique of an optical transfer system.

  Hereinafter, embodiments of the resist coating apparatus of the present invention will be specifically described with reference to the drawings. FIG. 1 is a plan view of an example of the resist coating apparatus of the present invention, and FIG. 2 is a front view. The resist coating apparatus 1 of the present invention has a motor 5 for rotating a disk-shaped disk substrate 3. The motor 5 has a rotating shaft 7. As shown in the figure, the rotary shaft 7 protrudes outside the motor 5 and holds the disc-shaped disk substrate 3 at the tip thereof in a detachable manner. An encoder 15 is disposed on the rotary shaft 7. The encoder 15 is used to detect the rotation reference position and angle of the rotating shaft 7. The motor 5 is mounted on a motor mounting base 9. The motor 5 can hold the disk-like disk substrate 3 and can be rotated precisely. For example, a spindle motor or a stepping motor can be used. Two inkjet heads 11a and 11b are arranged so as to sandwich the disk-shaped disk substrate 3 from both sides in a non-contact state. The inkjet heads 11a and 11b are supported by support arms 13a and 13b that are spaced apart from each other. The disk-shaped disk substrate 3 can enter the gap between the support arms 13a and 13b while rotating. The support arms 13 a and 13 b are fixed to the ink jet printer main body 15. Although not shown, the support arms 13a and 13b can be equipped with a resist solution supply tank for supplying a resist solution to each inkjet head. However, the resist solution supply tank can be arranged at other locations. The support arms 13 a and 13 b are mounted on a carriage (advance / retreat mechanism) 17. The carriage 17 can move the ink jet heads 11 a and 11 b forward and backward in the radial direction of the disk-shaped disk substrate 3. As the carriage 17, for example, any linear carriage, servo motor, stepping motor, ball screw, or other carriage capable of linear reciprocation can be used.

There are the following two methods for uniformly applying the resist coating amount per unit area on the disk surface by inkjet.
(A) A method in which the number of coating dots on one circumference is the same and the coating amount of one dot is adjusted by the radius. In the case of this method, the circumference increases from the center of the disk toward the outer side in the radial direction. Therefore, if the number of applied dots on one circumference is the same, the dot interval also increases near the outer periphery. For this reason, the application amount of 1 dot is increased near the outer periphery.
(B) The carriage is moved by spiral scanning while rotating the disk, and ejection signals are generated at equal time intervals on the spiral trajectory. At this time, the head position by the carriage movement and the spindle rotation speed are controlled so that the peripheral speed is constant. Since resist is applied on the spiral trajectory at equal time intervals, the resist application amount of one dot is the same, and the dot interval increases in inverse proportion to the radius as it becomes the inner periphery.

FIG. 3 is a block diagram showing an example of control of the resist coating method according to the present invention. With reference to FIG. 3, the operation of applying the resist solution simultaneously and concentrically on the back and front surfaces of the disk-shaped disk substrate will be described in the order of steps.
(1) First, the disk-shaped disk substrate 3 is mounted on the rotating shaft 7 of the spindle motor 5. A rotation reference position signal (index signal) and an angle signal of the rotary shaft 7 are transmitted from the encoder 15 to the control circuit 19. A signal for moving the carriage 17 to a resist application start point (for example, a predetermined radial position of the disk-shaped disk substrate 3) is transmitted from the control circuit 19, and when the carriage 17 is disposed at a predetermined position, the carriage 17 is moved to the predetermined position. A signal indicating the placement is transmitted to the control circuit.
(2) Thereafter, a rotation drive signal is transmitted from the control circuit 19 to the spindle motor 5 to rotate the spindle at a predetermined number of rotations. Based on the angle signal, a resist solution spray start signal is transmitted from the control circuit 19 to the ink jet heads 11a and 11b, and the resist solution is spray-coated on both surfaces of the disk-shaped disk substrate 3 at a preset angle pitch.
(3) While the spindle motor 5 is being driven, the rotation reference position signal (index signal) and the angle signal of the rotating shaft 7 are transmitted to the control circuit by the encoder 15. The encoder 15 detects whether or not the disk-shaped disk substrate 3 has been rotated once for a predetermined radius position. If it has not been rotated once, return to Step 2. When the encoder 15 detects that the disk-shaped disk substrate 3 has rotated once and transmits the signal to the control circuit 19, the control circuit 19 transmits a resist solution ejection stop signal to the inkjet heads 11a and 11b, and the spindle motor 5 Send a rotation stop signal.
(4) The control circuit 19 changes the ink jet driving voltage and changes the resist solution injection amount in accordance with the next radial position. This is to correct the equiangular circumferential distance due to the change in radius. As a result, it is possible to uniformly perform application per unit area on the disk surface by inkjet. For example, since the circumference of the disc-like disk substrate 3 is larger at the outer periphery, the number of dots is smaller than that at the smaller circumference near the center, so that the resist solution injection amount is increased for each dot.
(5) Next, the control circuit 19 transmits a signal for moving the carriage 17 in the predetermined direction of the disk-like disk substrate 3 by the distance in the horizontal direction of the head (one pitch or the print width).
(6) When it is detected that the carriage 17 has moved by one pitch, the operations (2) to (5) are repeated.
(7) The encoder 15 detects whether or not the carriage 17 has reached the application end point. When the carriage 17 has not reached the application end point, the above-described (2) to (6) until the carriage 17 reaches the application end point, that is, until the resist is applied to the entire application range of the disk-shaped disk substrate 3. ) Is repeated. When the carriage 17 has reached the application end point, the control circuit 19 drives the carriage 17 to move the ink jet heads 11 a and 11 b backward in the radial direction from the outer peripheral edge of the disk-shaped disk substrate 3. Thus, the resist can be simultaneously applied concentrically on both the front and back surfaces of the disk-shaped disk substrate. The carriage 17 can be moved from the outer peripheral edge of the disk-shaped disk substrate 3 toward the center, or conversely, can be moved from the center of the disk-shaped disk substrate 3 toward the outer peripheral edge.

Alternatively, the control circuit shown in FIG. 3 can simultaneously apply resist to both the front and back surfaces of the disk-shaped disk substrate by linking the linear reciprocation of the ink jet heads 11a and 11b and the rotational movement of the disk-shaped disk 3. It can be applied concentrically. In this case, a stepping motor is used as the motor instead of the spindle motor. For example,
(1) After the disk-shaped disk substrate 3 is mounted on the rotating shaft 7 of the stepping motor 5, the carriage 17 moves the inkjet heads 11a and 11b to the resist application start point of the disk-shaped disk substrate 3 (for example, the disk-shaped disk substrate 3 A signal indicating that it is arranged at a predetermined radius position) is transmitted from the carriage 17 to the control circuit 19.
(2) Next, a resist solution ejection start signal is transmitted from the control circuit 19 to the inkjet heads 11a and 11b, and a resist solution is applied to a predetermined location.
(3) Next, the control circuit 19 changes the inkjet drive voltage and changes the resist solution injection amount in accordance with the next radial position. This is to correct the equiangular circumferential distance due to the change in radius. As a result, it is possible to uniformly perform application per unit area on the disk surface by inkjet. For example, since the circumference of the disc-like disk substrate 3 is larger at the outer periphery, the number of dots is smaller than that at the smaller circumference near the center, so that the resist solution injection amount is increased for each dot.
(4) Next, the control circuit 19 moves the carriage 17 by one pitch in a predetermined direction (that is, inward or outward in the radial direction), and at the moving point, the resist solution injection amount changed in (3) above is obtained. Based on this, a resist solution injection start signal is transmitted to the inkjet heads 11a and 11b, and a resist solution is applied.
(5) The control circuit 19 detects whether or not the carriage 17 has moved from the application start point to the application end point in one radial direction. When the application end point has not been reached, the control circuit 19 repeats the operations (2) to (4).
(6) When the carriage 17 has reached the application end point, the control circuit 19 transmits a signal for returning the carriage 17 to the application start point, and at the same time, a rotation signal is transmitted to the stepping motor 5 and the rotation shaft 7 is set to a predetermined position. The encoder 15 transmits the rotation reference position signal (index signal) and angle signal of the rotating shaft 7 to the control circuit 19.
(7) The encoder 15 detects whether or not the disk-shaped disk substrate 3 has made one rotation. When the disk-shaped disk substrate 3 is not rotated once, the operations (2) to (6) are repeated. When the disk-shaped disk substrate 3 is rotated once, the control circuit 19 drives the carriage 17 to move the ink jet heads 11 a and 11 b backward in the radial direction from the outer peripheral edge of the disk-shaped disk substrate 3. Thus, the resist can be simultaneously applied concentrically on both the front and back surfaces of the disk-shaped disk substrate.

  4A is a partially enlarged schematic plan view of a resist pattern applied by a conventional technique, and FIG. 4B is a partially enlarged schematic plan view of a resist pattern applied by the resist coating apparatus of the present invention. As shown in FIG. 4A, when applying a resist to a disk-shaped disk substrate with a conventional ink jet printer, the resist 104 is applied while scanning the ink jet head or the substrate in the XY plane. A large number of resists 104 are generated which are linearly arranged and deviate from the tracks (imaginary lines in the drawing) of the disk-shaped disk substrate. Therefore, pattern transfer by the stamper 108 is also defective. On the other hand, as shown in FIG. 4B, according to the resist coating apparatus of the present invention, the resists 104 are arranged concentrically along the tracks (imaginary lines in the figure) of the disk-shaped disk substrate. The Thereby, accurate pattern transfer by the stamper 108 can be ensured.

  The preferred embodiments of the resist coating apparatus and the resist coating method of the present invention have been described above. However, the present invention is not limited to the illustrated embodiments, and various modifications can be made. For example, in FIGS. 1 and 2, the disk-shaped disk substrate is held and rotated vertically, but an embodiment in which the disk-shaped disk substrate 3 is held horizontally and rotated as shown in FIG. 5 is also possible. . Further, the resist 104 is applied not only to the dot pattern as shown in FIG. 4 but also to a continuous annular resist pattern as shown in FIG. 6 according to the shape of the fine pattern 106 of the stamper 108, for example. You can also.

  In addition, the resist coating apparatus of the present invention can simultaneously apply a resist to both the front and back surfaces of a disk-shaped disk substrate, but a use mode in which the resist is applied to only one of the surfaces is also possible.

DESCRIPTION OF SYMBOLS 1,1A Resist coating apparatus 3 Disc-shaped disk board | substrate 5 Motor 7 Rotating shaft 9 Motor mounting base 11a, 11b Inkjet head 13a, 13b Support arm
15 Encoder 17 Carriage 19 Control circuit 100 Transfer object 102 Substrate 104 Resist 106 Fine pattern 108 Stamper 110 Pattern layer

Claims (8)

A disk-shaped disk substrate rotation motor having a rotation shaft inserted into and removed from the through-hole of a disk-shaped disk substrate having a through-hole in the center, and arranged in a non-contact state on both sides of the front and back surfaces of the disk-shaped disk substrate And a carriage for moving the two inkjet heads back and forth in the radial direction of the disk-shaped disk substrate. 2. The resist coating apparatus according to claim 1, wherein the disk-shaped disk substrate rotation motor is a motor selected from the group consisting of a spindle motor and a stepping motor. The resist coating apparatus according to claim 1, wherein the two inkjet heads are respectively supported by two support arms spaced apart from each other. 2. The resist coating apparatus according to claim 1, wherein the carriage is a carriage capable of linear reciprocation selected from the group consisting of a linear motor, a servo motor, a stepping motor, and a ball screw. The resist coating apparatus according to claim 1, wherein an encoder is further disposed on the rotating shaft. A disk-shaped disk substrate having a through hole at the center is inserted into the rotation axis of the disk-shaped disk substrate rotation motor, and two inkjet heads are arranged in a non-contact state on both the front and back surfaces of the disk-shaped disk substrate. A resist coating method comprising: moving the two inkjet heads back and forth in the radial direction of the disk-shaped disk substrate while rotating the disk-shaped disk substrate by the disk-shaped disk substrate rotating motor. The resist coating method according to claim 6, wherein the resist is coated while the disk-shaped disk substrate is continuously rotated by a spindle motor. 7. The resist coating method according to claim 6, wherein the resist is coated while the disk-shaped disk substrate is rotated stepwise by a stepping motor.

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